President Obama's summit shows party differences to be as wide as ever. It makes clear that if Democrats hope to overhaul healthcare, they must go it alone.

Reporting from Washington — Facing unbending Republican opposition to a healthcare overhaul, President Obama confronted a stark reality Thursday as his televised summit ended: If he and his Democratic allies in Congress want to reshape the nation's healthcare system, they will have to do it by themselves.

Washington's most powerful Democrats and Republicans gathered for a remarkably detailed, deeply felt -- and occasionally sharp -- exchange on one of the most important and complex issues facing the country.

But what emerged with crystalline clarity were two parties with an unbridgeable disagreement over how to deal with the nation's healthcare crisis.

Republican lawmakers remained staunchly against the Democratic bid to use the federal government to regulate health insurance, subsidize coverage for tens of millions of Americans and force changes in the way medical care is provided.

"There are some fundamental differences that we cannot paper over," Senate Assistant Minority Leader Jon Kyl (R-Ariz.) told the president at the summit.

Obama acknowledged as much as he wrapped up the 7 1/2 -hour gathering. "I don't know, frankly, if we can close that gap," he said. "We cannot have another yearlong debate."

By underscoring the ideological chasm separating the two parties, Obama's summit set the stage for Democrats to pursue a go-it-alone endgame without any pretense of bipartisanship.

"We just can't quit. This is a once in a political lifetime opportunity to deal with a healthcare system that is really unsustainable," he said.

Obama now faces head-on the challenge of cementing Democratic support behind the healthcare blueprint he unveiled this week and rounding up the votes to push a legislative package through the House and Senate by the end of next month.

That process is expected to begin in earnest in a matter of days.

Even if the summit produced no breakthrough to bipartisanship, it brought onto the public stage a policy debate that for months had been taking place in the corridors, chambers and backrooms of Capitol Hill -- and in sound bites from both sides that were designed in large part to score political points.

The event, held in the Blair House, across the street from the White House, was widely derided in advance as political theater, pre-scripted as an infomercial and drained long before it began of any hope of producing substantive agreement.

But it marked what could be the beginning of the end of the long healthcare debate.

In the absence of any significant concessions by either side, Democrats are preparing to use a legislative procedure that will allow them to avoid a Republican filibuster in the Senate. They believe the summit could convince the public that the controversial strategy is a last resort.

For Republicans, the meeting was a forum to cast their opposition to the legislation not as partisan obstructionism but prudent policy.

As they have for months, they cited a fear of big change, rejecting Obama's call for legislation that would push the country toward universal health insurance coverage. Instead, they called for a step-by-step approach, warning of a "tyranny of the majority," as Sen. Lamar Alexander (R-Tenn.) said, quoting 19th century political philosopher Alexis de Tocqueville.

Throughout the day, Obama and other Democrats described their healthcare initiative as a reasoned, ideologically centrist solution.

"We all know this is urgent," Obama told 21 Democrats and 17 Republicans squeezed around tables arranged in a square.

"Unfortunately over the course of the year . . . this became a very ideological battle. It became a very partisan battle. And politics, I think, ended up trumping practical common sense."

Obama and other senior Democrats ticked off a list of provisions in their legislation that have been backed by Republicans, including initiatives to combat Medicare fraud, allow the interstate sale of health insurance, and help small businesses provide their employees health benefits.

The centerpiece of Democratic proposals to expand coverage -- a new marketplace, or exchange, in which commercial insurers would compete for business -- hews to GOP principles of preserving private health insurance rather than replacing it with new government programs.

And at a time when Republicans are demanding greater fiscal responsibility, the Democratic healthcare bills are projected to reduce the federal deficit over the next two decades, according to the nonpartisan Congressional Budget Office.

"We're not that far apart," said Senate Finance Committee Chairman Max Baucus (D-Mont.), a leading author of the Democratic healthcare legislation who spent nearly nine months last year working with Republicans on his bill. "We really are close."